• Journal of Korean Institute of Industrial Engineers
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• v.39 no.2
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• pp.90-98
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• 2013

The k-out-of-n system with mixed redundancy is defined as k-out-of-n system which both includes warm-standby and cold-standby components. In case that operating components in the system fail and the system needs quick transition of standby components to operation state, the k-out-of-n system with mixed redundancy is useful for decreasing system failure rate and operational cost. Reliability-Redundancy Optimization Problem (RROP) involves selection of components with multiple choices and redundancy levels for maximizing system reliability with constraints such as cost, weight, etc. A solution methodology by using harmony search algorithm for RROP of the k-out-of-n system with mixed redundancy to maximize system reliability was suggested in this study.

• The Korean Journal of Applied Statistics
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• v.26 no.1
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• pp.119-130
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• 2013

A system with $n$ components which functions when at least ${\kappa}$ of the components function is called ${\kappa}$-out-of-$n$ system. Most studies on ${\kappa}$-out-of-$n$ system derive the system reliability based on the assumption that the system has just two states: functioning or failed. However, the system efficiency may depend on the number of functioning components. This paper considers a Multi-state ${\kappa}$-out-of-$n$ system and derives the total system efficiency. In addition, assuming that the system is repairable, the optimal repair policy to maximize the system efficiency is studied. The system efficiency considered in this paper can be regarded as a generalized measure of the mean time to the failure of the system.

• Journal of the Korean Operations Research and Management Science Society
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• v.17 no.2
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• pp.123-130
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• 1992

The model of k-out-of n : G repairable system with identical components is extended to a repairable system with n different components. The objective is to analytically derive the mean time of the busy period for a k-out-of-n : G system with unrestricted repair. Then, the lower and upper bounds on the average time of the busy period of the n-component system with restricted repair are also shown.

• Proceedings of the Korean Society for Quality Management Conference
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• 2006.11a
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• pp.309-314
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• 2006

The linear Consecutive-k-out-of-n:F system consists of n component ordered linearly and fail if and only if at least k consecutive components fail. We assume that the components are independent and identical exponentially distributed. This paper develops a model to calculate the expected cost per unit time of a linear consecutive-k-out-of-n:F system. The optimization problem we consider regards the choice of the system structure parameter k to minimized the expected cost per unit time.

• Journal of the Korean Institute of Gas
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• v.17 no.1
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• pp.49-55
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• 2013

Large scale systems, the facilities for the production of power, gas and chemical, have the complex structures. Most systems require the high reliability for the improvement of process efficiency, but it is difficult to analyze the reliability of processes with complex structures. In this study, we investigated reliability path of chemical process with k-out-of-n system by reliability block diagram(RBD) and calculated the reliability of process through the failure enumeration method of reliability path. This method should help in analyzing the reliability of k-out-of-n system.

• Journal of applied mathematics & informatics
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• v.25 no.1_2
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• pp.389-405
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• 2007

In this paper, we study a k-out-of-n system with single server who provides service to external customers also. The system consists of two parts:(i) a main queue consisting of customers (failed components of the k-out-of-n system) and (ii) a pool (of finite capacity M) of external customers together with an orbit for external customers who find the pool full. An external customer who finds the pool full on arrival, joins the orbit with probability ${\gamma}$ and with probability $1-{\gamma}$ leaves the system forever. An orbital customer, who finds the pool full, at an epoch of repeated attempt, returns to orbit with probability ${\delta}\;(<\;1)$ and with probability $1-{\delta}$ leaves the system forever. We compute the steady state system size probability. Several performance measures are computed, numerical illustrations are provided.

• IE interfaces
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• v.21 no.3
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• pp.254-261
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• 2008

Connected-(r,s)-out of-(m,n) : F system is an important topic in redundancy design of the complex system reliability and it's maintenance policy. Previous studies applied Monte Carlo simulation and genetic, simulated annealing algorithms to tackle the difficulty of maintenance policy problem. These algorithms suggested most suitable maintenance cycle to optimize maintenance pattern of connected-(r,s)-out of-(m,n) : F system. However, genetic algorithm is required long execution time relatively and simulated annealing has improved computational time but rather poor solutions. In this paper, we propose the ant colony optimization approach for connected-(r,s)-out of-(m,n) : F system that determines maintenance cycle and minimum unit cost. Computational results prove that ant colony optimization algorithm is superior to genetic algorithm, simulated annealing and tabu search in both execution time and quality of solution.

• International Journal of Reliability and Applications
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• v.4 no.2
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• pp.51-56
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• 2003

A k-out-of-n system with n identical and independent components is considered in which the components takes two types of function: 0 (open-circuit) or 1 (closed) on command (e.g. electromagnetic relays and solid state switches). Components are subject to two types of failure on command: failure to close or failure to open. In our k-out-of-n system, failure of (n-k)＋1 or more components to close causes to the close failure of the system, or failure of k or more components to open causes the open failure of the system. The long-run average cost rate is obtained. We find the optimal k minimizing the long run average cost rate for given n. A numerical example is presented.

• Journal of Korean Society for Quality Management
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• v.21 no.1
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• pp.121-135
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• 1993

The derived expressions and computations of the system reliability in the consecutive k out of n failure structure with sink-source pole are discussed and a new simplified formulation to compute the reliability of consecutive k out of $n^*$ failure system is presented, and the relations with system reliability when the number of first consecutive falied components from source is greater than k are presented in this paper. The new simplified formulation is illustrated in the numerical experiments.

• Journal of Korean Institute of Industrial Engineers
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• v.26 no.2
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• pp.128-135
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• 2000

This paper considers a consecutive k-out-of-n:F system when the failure of a component in the system induces higher failure rate of the preceding survivor. The reliability, mean time to failure(MTTF), and average failure number of a consecutive k-out-of-n:F system are obtained, when the failure of a component increases the failure rate of the survivor which is working just before the failed component. Then the optimal number of consecutive failed components to minimize this long run average cost rate can be obtained. An example is considered to calculate the reliability, MTTF and average failure number of the system. And two procedures that find the optimal number of consecutive failed components are studied. Then, various cases of system parameters are also studied.